Hello,
I have a question about a type of ant we have here in south Texas. Here in Hebbronville we have an ant that sound very much like the Paraponera ant. The ant has a VERY painful sting and it is large and black. The sting is much more painful than that of our native gold scorpions. just wondering what type of ant this may be. They live at the base of older Mesquite trees and my grandparents use to call them "palmoranas" thats a Spanish word for these ants.

Thank you,
Daniel

Dear Daniel,

There are over 140 species of ants known from Texas. You can see a list of the species and images of most of them here.

Without seeing the ant it is hard to be sure what species you are encountering, but I can tell you it is not Paraponera clavata since this ant is not found that far north. You can see a map of the known distribution here.

The ant with the painful sting is likely a species of Pachycondyla if they mostly forage on the ground. These ants are know to be aggressive and have painful stings when disturbed. On the other hand if the ants run up and down the mesquite tree then they could be a species of Pseudomyrmex, which can also have painful stings.

I hope you continue to observe all the diverse and beautiful ants around you!

Fire ants in our area often form lines of mounds along a street curb. Today I noticed a different pattern. This pattern consisted of a dozen, or more, fire ant mounds spaced in a more-or-less equidistant distribution in a large mowed lawn. Space between mounds averaged about 20 feet. I assume that these mounds represent separate colonies? How does one account for the spacing? It does not appear to be random. Is there some mechanism by which some ants from a colony move to a new location in response to some stimulus? Is the adaptive advantage of this dispersal pattern related to food abundance? What initiates sub-colony movement: new queen, reduction in available food, some scent left by ants that builds up as they exploit a site? Have there been studies of fire ant behavior in relation to the resource base? If my observation is accurate, this behavior should maximize efficiency of resource use.

Vincent

Hi Vincent,

Your observation of regular spacing among fire ant colonies is astute and similar to patterns you will see in lawns, pastures, and roadsides across the southeastern US, Texas, California, eastern Australia, and now parts of China. This natural patterning is a characteristic of dense monogyne (single queen form) fire ant populations. Each mound is the home of an individual colony with one queen. The space between colonies is "territory" which is divided up among adjacent colonies, usually in a rank order, where the largest colonies (which often have the largest mounds, too) occupy the largest territories.

Fire ants, especially the red imported fire ant, Solenopsis invicta, are one of the relatively few ant species that maintain absolute territories; that is, they guard and defend an area around the colony (mound), not just the mound itself, from any and all threats. Most other ant species defend only the nest, foraging trails, and food resources, so fire ants are a little unusual because of the amount of effort they put into maintaining their territories. Defense of a territory is probably an evolved response to intraspecific competitive pressure, that is, the fact that neighboring fire ant colonies are really good at competing with one another. The safest way to prevent having all of your food eaten or, more likely, your whole family captured and killed by neighboring fire ant colonies is to maintain a territory, remaining vigilant and defensive to any intrusion into the territory.

Maintenance of the colony boundaries is dependent largely on the interactions among a small number of individuals that scout around the boundaries of the territories. They respond to contact with non-nestmate ants by running away (in small numbers or as individuals, fire ant workers are actually rather timid when away from the nest). Thus, in zones of frequent contact at the edge of territories there actually exists a "no ants land" where there are very few individuals because they are "repelled" from one another by regular contact with non-nestmates. If they do not encounter ants from neighboring colonies they will, collectively, forage further and further from their territory. This thermostatic "control" of colony boundaries ensures that if, say, a neighbor colony suddenly dies, then its territory will rapidly be subsumed into one or more neighboring colonies' territory. As you can imagine, this kind of territoriality requires a large number of workers to maintain.

To the best of our knowledge, fire ant colonies generally do not appear to be resource limited or pathogen/parasite limited to the extent that it would drive frequent colony movements across populations. Fire ants, like most ants, are omnivorous and will opportunistically feed upon a wide range of food items. Colonies may, however, frequently be protein limited, but this does not appear to reach starvation levels that prompt a "move or die" scenario resulting from the resource base within the territory being completely depleted. Nevertheless, fire ant diet is an active area of research, as is territory maintenance. The best, and most complete work on fire ant territoriality has been carried out by my good friend Dr. Walter Tschinkel at Florida State University. Google him sometime and take a look at some of his papers or his book, The Fire Ants, if you would like to learn more!

Like many questions in ecology, this question has a few different kinds of answers: short, long, and "are you asking the right question?" I'll give them to you in order, as best as I can.

Short: No.

Long: In their book "Ant Ecology," Lach, Parr, and Abbott (2010) quote Holldobler and Wilson (1990) in saying that "The estimated 10,000 trillion individual ants alive at any one time weigh about as much as all human beings combined." But the main reason the answer to your question is "no" is that ants are not a single species (please see an earlier post about how many species of ants there might be). Ants are a taxonomic family with more than 14,000 described species and subspecies, so it's really unfair to compare their biomass with, say, leopards or bull frogs. Or humans or Antarctic krill.

There are several studies out that indicate that ants are a very important part of ecosystems where they occur. The biomass of ants in tropical rainforests is thought to often be greater than that the biomass of all vertebrates in the rainforest combined. But the measurements necessary to make claims like these were really only taken in a few studies. (one such study, Fittkau and Klinge 1973, is linked here, and a study that assesses ant prevalence in tropical rainforest canopies, Davidson et al. 2003, is linked here ) It is very time-consuming to count all the dead ants that fall out a tree after you have fogged it with insecticide, so comparable studies have not been done in many parts of the world.

It is important to note (much as it pains me, as a myrmecologist) that the world-wide population of termites has been estimated at about 27 times higher than the ant population in a paper by Zimmerman et al. 1982. (linked here) Although I don't know what the average biomass of a termite is, I suspect that it is not 27 times less than your average ant, so termites are also in the running for insect group with the most mass. I think that the population estimates and biomass estimates for both insect groups, however, are very rough, and either could be off by a decimal place here or there. Because this is AntWeb, I'll say that the issue of who has more biomass, ants or termites, is up for debate. A more isoptera-centric blog might argue otherwise.

Worldwide biomass estimates for individual species are very difficult to come by. The most rigorous estimates are for humans and domesticated animals. There are probably a little more than 6.7 billion humans alive right now, and together, we might weigh as much as 335,000,000,000 kg (or 737,000,000,000 lbs.) This figure is based on an average human weight of more than 100lbs, though (50kg, to be exact). I don't know how accurate this estimate is, especially considering that about 1/3 of us are children. There are supposedly around 1.3 billion cattle in the world, and, put together, they may weigh almost twice as much as our species.

The only non-domestic, super-abundant species for which serious attempts have been made at estimating biomass is a type of shrimp that lives in the cold waters around Antarctica: the Antarctic krill, Euphausia superba,. They are the primary food for many fish and baleen whales (suborder Mysticeti). In a really interesting study (click here for more) Atkinson and colleagues (2009) calculated the world biomass of krill to be between 117 and 379,000,000,000 kg (note that the upper estimate is slightly above what people have suggested for the total human biomass). Truly, these organisms are successful. They might be the only wild species that could compete with Homo sapiens for the title of "species with the most biomass."

However, we can't forget that as much animal biomass as there is, there is even more plant and bacterial biomass. Probably at least ten times as much as the biomass of all animals put together. Scientists still argue about which has more biomass on earth: bacteria or plants. Worldwide, they both probably have about the same amount of Carbon, but Bacteria probably contain about 10 times more Nitrogen and Phosphorus (read more here ) Like ants, though, there are many many species of bacteria and plants, and I don't know of any studies that attempt to estimate world-wide biomass for a single species of either.

"Are you asking the right question?" In ecological studies, there has been a lot of emphasis placed on using biomass as an indication of an organism or group of organism's importance in the ecosystem. However, what is at least as important is how quickly organisms use resources. For example, because they have higher metabolisms, a million ruby-throated hummingbirds will consume much more food than one African Elephant, even though both have about the same biomass (3,000kg, or 3.3 US tons). Thus, ants, as a group, may actually consume more resources per year than antarctic krill, even though both may have roughly the same biomass, because ants tend to be smaller, and live in warmer environments. Although there may be about 10-15 times the biomass of termites than cows in the world, studies have suggested that termites might produce almost 30,000 times as much methane per year because of their faster metabolism. Humans are larger than ants and krill, and so should have slower metabolisms, but I'm sure we have a much larger ecological footprint than either species, and thus have much more of an impact on our environment. When you factor in all of the oil and coal we use in industry and our daily lives, we are definitely the most ecologically significant animal taxon.

Dear AntAsk,
In mid May at about 6:00 in the evening in Ann Arbor, Michigan, USA, I was walking along the sidewalk and saw some small black ants swarming. I like to watch queens come out so I sat down to watch. I stayed about 45 minutes and I didn't see a single wing. What I did see was amazing. After a few minutes the ants started forming patterns. Two ants that were narrower than most would lock jaws. Then two normal ants would grab onto the heads of these two to form a plus sign or X. They would stay like that for 6-7 minutes then breakup. Sometimes 4 more of the normal ants would grab onto the abdomens of the 4 ants and form a plus sign of eight ants. In the time I was there there were always 15 to 30 of these symbols. I am not sure how many separate nests were participating. I left to get a camera and a collecting jar. When I came back the show was over. Is this common behavior? I have not seen it before.

-Dave

Dear Dave,

That definitely sounds like an interesting behavior. If all of your ants were roughly the same size, dark brown/black, and on a sidewalk, chances are you're looking at Tetramorium caespitum, the so-called "pavement ant."

Most of the time when you see large groups of these ants congregating, they are fighting. These ants are often very aggressive to members of their own species, and neighboring colonies will often engage in territorial "wars." My guess is that the "plus signs" you observed were actually groups of ants biting on and attempting to subdue each other. Please see a fantastic photograph by Alex Wild of such a scene by clicking here. After such battles, it is not unusual to see wounded ants with the heads of their enemies still latched on to their legs or antennae.

Hi there,
I have two questions:
1) If you were going to do an experiment on Argentine ants and wanted them to from a trail to a food source, what food would you use. (My son is doing a paper/ behavioral experiment on pheromone trails). We've placed banana and white sugar near a nest and after a day only a few ants were at the sugar. At this rate it will take forever to do the observations and experiment design!
2) There appears to be quite a few ants under a specific rock in our garden. Last week, I just happened to lift the rock and saw tons of Argentine ants swarming around carrying what looked like tiny white flakes of something in their mandibles. What was this? I went in the house to try and locate a video camera. It took me awhile to do so, and when I returned and lifted the rock, they were gone!

Thanks in advance for your time. I look forward to hearing from you.
~Joanne

Hi Joanne!

Thanks for contacting us at AntAsk! How exciting that your son is doing an experiment on ant behavior! Ants are so much fun to study! Concerning your first question: Many researchers use tuna to bait their ants. Of course, this can get kind of smelly, but since you already tried sugar and banana, you might want to try tuna. One other option could be jam. For my research I bait ants using a sugar solution (I work on ants that only feed on plant sap in nature, so they especially like sugar). You could try solving sugar and place little drops on little plastic pieces, if you don't like to tuna option. I suggest solving sugar in water in the ration 1:3 (e.g., one tea spoon of sugar and 3 tea spoons of water).

Concerning your second question: Ants often have their nest or part of their nest under rocks. So I guess that you saw the brood of the ant colony. The ant queen lays eggs, from these larvae hatch. The larvae grow, so they come in different sizes and eventually they pupate. So I guess you saw eggs, larvae and pupae. Once you lifted the rock, the ant workers tried to bring the brood to safety. This is why they were all gone when you came back.

This image shows from left to right: a worker, a small larva, medium larva, large larva, a young pupa and an old pupa of the species Pseudomyrmex gracilis. Photo curtesy by Alex Wild.

Let us know how your son's experiments go and contact us if you have any further questions!

I am an American living in Vietnam working with the US government to return POW/MIA from the Vietnam war to their families. I have built a nice home for some lucky ants and I would like to know your recommendation for a larger, easy to keep species that can be found locally.

Thank You
John

Dear John,

Since you work in Vietnam, I am sure you have plenty of amazing ants to choose from. We have addressed similar questions here, here, and here. Hopefully these will be helpful.

In addition, there is a website on the ants of Vietnam that you can find here.

I live in southeastern Pennsylvania and have for forty years. For the first time this year, I have very tiny ants that collect bits of dried leaves, insect parts, etc and pile them up in little piles. on a brick porch. I think the piles are at the opening that leads to the nest. What are they?

Sue, PA, USA

Dear Sue,

This is a very interesting question and without seeing the piles myself I have two guesses: Either the ants pile up dirt that comes up when they build a tunnel system in the ground or the piles are waste dumps. If the piles are located on the entrance to the nest, this might indicate that the ants have built a large subterranean tunnel system. The dirt that is being removed to form the tunnels is then piled up at the nest entrance (see picture below for an example).

This picutre by Alex Wild shows the nest entrance of an Dorymyrmex bureni colony.

Since you mentioned that the ants also deposit dried leaves and insect parts on the piles, they might be waste dumps. Since ants live in colonies with large numbers, diseases can spread easily and ants have developed hygienic behaviors to deal with this. Please read this post to find out more on hygienic behavior in ants.

Hi there,
I live in Charleston, SC and my husband took this picture of these ants outside his workplace. Can you identify them for us?

Thanks,
Torie

- AND-

Hi,

One of my friends photographed what we think is some kind of ants here in Sri Lanka !! not quite sure the name of these ants

is it possible to identify ?

Thanks in advance,

Shashika

Dear Torie and Shashika,

Thank you for contacting AntAsk and sending a photos of your "ants" in question. What you have found are not ants, but a group of hemiptera insects that looks a lot like ants! There are lots of insects and spiders that mimic ants and we have a couple posts on this already here, here, and here.

I have heard and read much about how ants communicate to each other using pheromones. My question is how far away (in body lengths or inches) can an ant "smell" these signals. Also, by what other senses do ants navigate around the world.

Appreciatively,
Blake

Dear Blake,

This is an interesting question, and we definitely still have much to learn about how ants sense and interpret their surroundings.

Ants vary greatly in their ability to see things and form images. Some ants are completely blind, and many ants have small eyes that can probably only distinguish light, dark, and movement. However, some ants have enormous eyes, as you can see in this iconic picture by Alex Wild.
Some ants have been shown to use visual cues to navigate, and some, like bees, can sense the polarity of sunlight.

However, most ants primarily perceive the world through smell and touch. The majority of ant communication happens in direct proximity to another ant from the same colony. The ants will tap each others antennae, and insodoing, "smell" and feel the texture of the other ant's cuticle. I wrote "smell" in quotation marks, because when something is "smelled," we usually talk about the detection of airborn chemicals. What ants are really doing in this situation is "contact chemoreception," which, I suppose, is more similar to our sense of taste. At any rate, contact chemoreception, and the tactile interpretation of cuticle structure are the two most important parts of nestmate recognition in ants. We know this because there are some species of beetles and other insects which look nothing like ants, but are able to fool them into accepting them as sisters because of carefully matched cuticle texture and "smells."

But, as you indicated, ants also communicate by pheromones, which are airborn chemical messages. The pheromone in ants that we observe most commonly is the alarm pheromone. These compounds are often detectable by ants in very small amounts, but they diffuse to undetectable amounts in less than a minute in still air (which is good, in some cases, because the cause of the alarm may have already been taken care of--think of the neighbor's car alarm that won't stop honking.) Several studies in which researchers quantified the distance that ants are aware of alarm pheromones are reviewed in the recent book "The Superorganism," by Bert Holldobler and EO Wilson (2009). They gave 6cm (or about 2.5 inches) as the maximum distance a particular species of harvester ants would respond to an alarm pheromone in still air. Weaver ants, native to Australia and Southeast Asia, have been shown to respond to alarm pheromones from more than 10cm away (a little less than 4 inches). These distances would obviously change with wind direction.

An area of ant pheromone signaling we know much less about is mate-calling. This is obviously the most interesting use of pheromones to humans and many other animals. Male moths might fly more than a mile to find a mate, if the wind is going in the right direction. Some ants are known to use pheromones to attract mates (generally the females stay put and the males "follow their nose"), but over what distances these chemicals work is quite a mystery. However, one noteworthy trait of many male moths is their feathery, fern-shaped antennae. This shape helps to maximize the number of chemoreceptors a male moth might have, increasing his chances of smelling a pheromone molecule. The antennae of male ants are much more drab, which suggests that the distances across which they can perceive pheromones are shorter than male moths.

Further information about pheromones can be found in this excellent blog post by "Wild About Ants," and in the book "The Superorganism," mentioned above.
I hope this helps!
Best,
Jesse Czekanski-Moir & the AntAsk Team